Influence of Holding Time on Properties of Cemented Carbide-polycrystallineDiamond Compact Joints

摘要

The influence of brazing holding time on properties of cemented carbide-polycrystalline diamond (PCD)compact joints were investigated in this study. The microstructure and phase composition of joints were investigated byscanning electron microscopy, electron probe microanalyzer, and X-ray diffraction. Microstructural investigationsrevealed the presence of Ag-based solid solution, Cu-based solid solution, Cu0.64Zn0.36, and a small amount of MnNi phaseat the joint interface. The max shear strength of brazed joints 350.6 MPa was determined in the samples joined at 15 s,which was partially due to the dispersion strengthening effect of gray-black grains containing Cu-based solid solution,Cu0.64Zn0.36 and MnNi phase in the joints. Equal-area-circle grain diameter of the gray-black grains grew with longerholding time, whereas the shear strength decreased because of the formation of continuous intermetallic compounds layeralong the joint boundary. Thermal damage of the PCD layer also deteriorated with increased holding time, and henceshorter holding time was preferable in the production.